Welcome to the forum, DYMOND, glad you have joined us.
I don't use Black Powder, but are you saying that no one in the area carries ANY brand of BP, or that they don't carry Goex? I believe there are a couple of other makers of BP that should work well for you if you prefer to stick with black. Many people use substitutes these days - Hodgdon's Pyrodex or Triple Se7en (777). There are also others, such as American Pioneer Powder (APP) and others you will read about on here, as well as the pro's and con's of each.
You mentioned Williams gun sight - do you live in the Flint, MI area? I am in this area. Williams may have other locations, I don't know.
I thought that Cabela's carried Goex, but I just did a search of Cabela's, Midsouth Shooters Supply and Midway USA, and NONE of them list any real Black Powder! I had no idea - but I'm sure that avid BP users here already know how hard it's getting to obtain.
I'm sure you'll get other replies to this post with more info, so keep lookin'. Good Luck!

IM jaybe